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Module: ActiveRecord::ConnectionAdapters::QueryCache

Relationships & Source Files
Namespace Children
Modules:
ConnectionPoolConfiguration
Classes:
Store
Defined in: activerecord/lib/active_record/connection_adapters/abstract/query_cache.rb

Constant Summary

Class Attribute Summary

Class Method Summary

Instance Attribute Summary

Instance Method Summary

Class Attribute Details

.enabled_by_default (rw)

This method is for internal use only.
[ GitHub ] 

  


# File 'activerecord/lib/active_record/connection_adapters/abstract/query_cache.rb', line 13



def enabled_by_default # :nodoc:
  ActiveSupport::IsolatedExecutionState[:active_record_query_cache_enabled] || false
end


  








  

    .enabled_by_default=(enabled)   (rw)
  

  

    This method is for internal use only.
  

  [ GitHub ]


  

  


# File 'activerecord/lib/active_record/connection_adapters/abstract/query_cache.rb', line 17



def enabled_by_default=(enabled) # :nodoc:
  ActiveSupport::IsolatedExecutionState[:active_record_query_cache_enabled] = enabled
end


  







Class Method Details



  

    .dirties_query_cache(base, *method_names)  
  

  [ GitHub ]


  

  


# File 'activerecord/lib/active_record/connection_adapters/abstract/query_cache.rb', line 27



def dirties_query_cache(base, *method_names)
  method_names.each do |method_name|
    base.class_eval <<-end_code, __FILE__, __LINE__ + 1
      def #{method_name}(...)
        if pool.dirties_query_cache
          ActiveRecord::Base.clear_query_caches_for_current_thread
        end
        super
      end
    end_code
  end
end


  








  

    .included(base)  
  

  

    This method is for internal use only.
  

  [ GitHub ]


  

  


# File 'activerecord/lib/active_record/connection_adapters/abstract/query_cache.rb', line 21



def included(base) # :nodoc:
  dirties_query_cache base, :exec_query, :execute, :create, :insert, :update, :update_with_result,
    :delete, :truncate, :truncate_tables, :rollback_to_savepoint, :rollback_db_transaction,
    :restart_db_transaction, :exec_insert_all
end


  







Instance Attribute Details



  

    #query_cache   (rw)
  

  [ GitHub ]


  

  


# File 'activerecord/lib/active_record/connection_adapters/abstract/query_cache.rb', line 213



def query_cache
  if @pinned && @owner != ActiveSupport::IsolatedExecutionState.context
    # With transactional tests, if the connection is pinned, any thread
    # other than the one that pinned the connection need to go through the
    # query cache pool, so each thread get a different cache.
    pool.query_cache
  else
    @query_cache
  end
end


  








  

    #query_cache=(value)   (rw)
  

  [ GitHub ]


  

  


# File 'activerecord/lib/active_record/connection_adapters/abstract/query_cache.rb', line 211



attr_writer :query_cache


  







Instance Method Details



  

    #cache(&block)  
  



  

    
Enable the query cache within the block.

  



  [ GitHub ]


  

  


# File 'activerecord/lib/active_record/connection_adapters/abstract/query_cache.rb', line 229



def cache(&block)
  pool.enable_query_cache(&block)
end


  








  

    #cache_notification_info(sql, name, binds)   (private)
  



  

    
Database adapters can override this method to
provide custom cache information.

  



  [ GitHub ]


  

  


# File 'activerecord/lib/active_record/connection_adapters/abstract/query_cache.rb', line 332



def cache_notification_info(sql, name, binds)
  {
    sql: sql,
    binds: binds,
    type_casted_binds: -> { type_casted_binds(binds) },
    name: name,
    connection: self,
    transaction: current_transaction.user_transaction.presence,
    cached: true
  }
end


  








  

    #cache_notification_info_result(sql, name, binds, result)   (private)
  

  [ GitHub ]


  

  


# File 'activerecord/lib/active_record/connection_adapters/abstract/query_cache.rb', line 324



def cache_notification_info_result(sql, name, binds, result)
  payload = cache_notification_info(sql, name, binds)
  payload[:row_count] = result.length
  payload
end


  








  

    #cache_sql(sql, name, binds)   (private)
  

  [ GitHub ]


  

  


# File 'activerecord/lib/active_record/connection_adapters/abstract/query_cache.rb', line 302



def cache_sql(sql, name, binds)
  key = binds.empty? ? sql : [sql, binds]
  result = nil
  hit = true

  @lock.synchronize do
    result = query_cache.compute_if_absent(key) do
      hit = false
      yield
    end
  end

  if hit
    ActiveSupport::Notifications.instrument(
      "sql.active_record",
      cache_notification_info_result(sql, name, binds, result)
    )
  end

  result.dup
end


  








  

    #clear_query_cache  
  



  

    
Clears the query cache.


One reason you may wish to call this method explicitly is between queries
that ask the database to randomize results. Otherwise the cache would see
the same SQL query and repeatedly return the same result each time, silently
undermining the randomness you were expecting.

  



  [ GitHub ]


  

  


# File 'activerecord/lib/active_record/connection_adapters/abstract/query_cache.rb', line 255



def clear_query_cache
  pool.clear_query_cache
end


  








  

    #disable_query_cache!  
  

  [ GitHub ]


  

  


# File 'activerecord/lib/active_record/connection_adapters/abstract/query_cache.rb', line 245



def disable_query_cache!
  pool.disable_query_cache!
end


  








  

    #enable_query_cache!  
  

  [ GitHub ]


  

  


# File 'activerecord/lib/active_record/connection_adapters/abstract/query_cache.rb', line 233



def enable_query_cache!
  pool.enable_query_cache!
end


  








  

    #initialize  
  

  [ GitHub ]


  

  


# File 'activerecord/lib/active_record/connection_adapters/abstract/query_cache.rb', line 206



def initialize(*)
  super
  @query_cache = nil
end


  








  

    #lookup_sql_cache(sql, name, binds)   (private)
  

  [ GitHub ]


  

  


# File 'activerecord/lib/active_record/connection_adapters/abstract/query_cache.rb', line 284



def lookup_sql_cache(sql, name, binds)
  key = binds.empty? ? sql : [sql, binds]

  result = nil
  @lock.synchronize do
    result = query_cache[key]
  end

  if result
    ActiveSupport::Notifications.instrument(
      "sql.active_record",
      cache_notification_info_result(sql, name, binds, result)
    )
  end

  result
end


  








  

    #query_cache_enabled  
  

  [ GitHub ]


  

  


# File 'activerecord/lib/active_record/connection_adapters/abstract/query_cache.rb', line 224



def query_cache_enabled
  query_cache&.enabled?
end


  








  

    #select_all(arel, name = nil, binds = [], preparable: nil, async: false, allow_retry: false)  
  

  

    This method is for internal use only.
  

  [ GitHub ]


  

  


# File 'activerecord/lib/active_record/connection_adapters/abstract/query_cache.rb', line 259



def select_all(arel, name = nil, binds = [], preparable: nil, async: false, allow_retry: false) # :nodoc:
  arel = arel_from_relation(arel)

  # If arel is locked this is a SELECT ... FOR UPDATE or somesuch.
  # Such queries should not be cached.
  if query_cache_enabled && !(arel.respond_to?(:locked) && arel.locked)
    sql, binds, preparable, allow_retry = to_sql_and_binds(arel, binds, preparable, allow_retry)

    if async
      result = lookup_sql_cache(sql, name, binds) || super(sql, name, binds, preparable: preparable, async: async, allow_retry: allow_retry)
      FutureResult.wrap(result)
    else
      result = cache_sql(sql, name, binds) { super(sql, name, binds, preparable: preparable, async: async, allow_retry: allow_retry) }
      result.shuffle_rows(arel)
    end
  else
    super
  end
end


  








  

    #uncached(dirties: true, &block)  
  



  

    
Disable the query cache within the block.


Set dirties: false to prevent query caches on all connections from being cleared by write operations.
(By default, write operations dirty all connections' query caches in case they are replicas whose cache would now be outdated.)

  



  [ GitHub ]


  

  


# File 'activerecord/lib/active_record/connection_adapters/abstract/query_cache.rb', line 241



def uncached(dirties: true, &block)
  pool.disable_query_cache(dirties: dirties, &block)
end


  








  

    #unset_query_cache!   (private)
  

  [ GitHub ]


  

  


# File 'activerecord/lib/active_record/connection_adapters/abstract/query_cache.rb', line 280



def unset_query_cache!
  @query_cache = nil
end